Electronic timepiece

ABSTRACT

An electronic timepiece in accordance with the present invention includes a time clocking circuit for counting reference signals from a reference signal generating circuit to provide time information as its output; a warning device for warning the user of a specific time, by use of vibrations or a buzzer, on the basis of time information derived from the time clocking circuit; and a timepiece state detection device for detecting the states of the temperature and the power source voltage of the timepiece and, if the detection values deviate from predetermined values, the detection device operates to stop the warning action of the warning means. The timings of time information derived from the time clocking circuit differ from each other between when the timepiece state detection device has detected a low temperature of the timepiece and when it has detected a low voltage at the power source, and differ from the time information timing at the normal state. This prevents any batteries&#39; consumption which may otherwise be caused by the meaningless warning, and makes it possible to inform the user of the states of the timepiece through the movement of the hands.

TECHNICAL FIELD

The present invention relates generally to an electronic timepieceequipped with additional functions such as an alarm function, and moreparticularly to an electronic timepiece ensuring effective utilizationof a battery acting as a power source for the electronic timepiece andhaving a capacity to inform the user of the state of the battery and thetemperature in the electronic timepiece.

BACKGROUND ART

It is desirable that the electronic timepieces using the batteriesdisplay time as long as possible without need to change the batteries.For this reason, used in the electronic timepieces, particularly inelectronic wristwatches desired to be extremely small and thin arebatteries having a very low self discharge rate and a less selfdegradation in spite of the long-term use.

Therefore, prevailing wristwatches are designed so that most of thefunctions included in the electronic timepieces operates with a minimumamount of electrical current and that the operation is averaged to allowa single battery to provide a time display for two or three years. Majorwristwatches with the alarm function for instance make use of apiezoelectric device-actuated buzzer. In this type of timepieces, thepiezoelectric device-actuated buzzer often uses a maximum instantaneouscurrent of about 7 mA and an average current of about 2 mA, whichenables it to have a battery life of more than two years if the alarm isused once a day.

Another type of electronic timepiece has also been developed andcommercially available which employs as the alarm function not onlynoise warning means operated by the piezoelectric buzzer but alsonoiseless warning means operated by a vibration motor.

However, the electrical current required to start the vibration motor,even when using a low electricity consuming motor, is 15 mA or more, andeven when it runs at its steady speed, 5 mA is required.

On the other hand, silver or lithium batteries utilized in general bywristwatches produce only a limited amount of electricity flow due totheir high internal impedance values. On top of this, at lowtemperatures of 5° C. or below these batteries' internal impedancerises, making it difficult to derive the electrical current therefrom.

Thus, if the vibration motor is started when the temperature is below 5°C., the battery voltage levels suddenly drop and even the operation ofthe time clocking circuit becomes stressed, the hands on the watch stopmoving.

However, when the watch is worn on the wrist, it is usual for the watchitself to have a temperature of about 30° C. due to the heat radiatedfrom the wearer's body, although the temperature of the watch itself maydrop to 5° C. or below if the watch worn on the wrist is in cold wateror if the watch is left at a low temperature, in which occasion thevibration motor's silent alarm is not particularly necessary. In thissituation starting the vibration motor results in an unnecessary wasteof the batteries and also needlessly shortens the watch's battery life.

In addition, in case a watch user has been aware that the vibrationmotor of the watch being left for some time has stopped, confusion couldbe avoided, if the owner could tell whether the vibration motor hasstopped due to a dead battery or the temperature.

DISCLOSURE OF THE INVENTION

It is therefore the object of the present invention to provide anelectronic timepiece which prevents any unnecessary waste of batteriesand indicates to the user the present state of the batteries andtemperature in the timepiece through the manner of movement of the handson the timepiece.

An electronic timepiece in accordance with the present inventioncomprises a reference signal generating circuit for generating referencesignals; a time clocking circuit for counting the reference signals toprovide time information as its output; warning means for warning theuser of a specific time on the basis of the time information derivedfrom the time clocking circuit; and detection means for detecting thestate of the timepiece and, if the detected value deviates from apredetermined value, bringing the action of the warning means to a stop;the warning means including noise warning means comprised of a buzzerand silent warning means comprised of a vibration motor, wherein thestate of the temperature and the power source voltage in the timepieceis detected.

It is thus possible to prohibit the operation of the vibration motorwhich requires large volumes of electrical current, in a low temperaturestate where the batteries are incapable of discharging the large volumesof current due to their characteristics, thereby ensuring a precise handmovement which is a duty of the timepiece.

Furthermore, the second hand movement mode at the low battery voltage iscaused to differ from that at the low temperature so that the user cantell whether the vibration motor does not operate due to short batterylife or due to low temperature.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a circuit part in an analog display typeelectronic timepiece showing an embodiment of the present invention;

FIGS. 2(a) and 2(b) are schematic top plan views of the analog displaytype electronic timepiece; and

FIG. 3 shows waveforms of hand movement signals DS1, DS2 and DS3.

BEST MODE FOR CARRYING OUT THE INVENTION

With reference to the accompanying drawings, description will now bemade for an embodiment in which the present invention is applied to ananalog display type electronic timepiece.

FIG. 1 is a block diagram of a circuit part in the electronic timepiecewith vibration alarm function in accordance with this embodiment. FIG. 2is a top plan view illustrating a display face of the electronictimepiece shown in FIG. 1. FIG. 3 is a signal waveform diagramillustrating outputs of hand movement signals DS in respective statesshown in FIG. 1.

Referring first to FIG. 1, a reference signal generating circuit 1provides as its outputs a hand movement reference signal KS providing atime reference for movements of the hands on the timepiece, atemperature detection timing signal TS indicating the timing at which adetection of the temperature is performed, and a voltage detectiontiming signal VS indicating the timing at which a detection of thebattery voltage is performed.

A time clocking circuit 2 receives as its input the hand movementreference signal KS and provides as its outputs hand movement signalsDS1, DS2 and DS3 at a cycle of one second in the ordinary state. Upon areceipt of a reset signal RS, the time clocking circuit 2 is reset tocease from outputting the hand movement signals DS1, DS2 and DS3.Furthermore, the time clocking circuit 2 counts the hand movementreference signal KS to output time data KL on a minute basis. These timedata KL represent a count number per minute from a point of time whenthe reset signal RS has been cleared.

A voltage detection circuit 3 detects the voltage of a battery not shownwhen it receives the voltage detection timing signal VS from thereference signal generating circuit 1. The voltage detection circuit 3provides as its output a voltage drop signal BD when the detectedbattery voltage is a predetermined voltage or below.

A temperature detection circuit 4 detects the temperature of thetimepiece when it receives as its input the temperature detection timingsignal TS from the reference signal generating circuit 1. Furthermore,the temperature detection circuit 4 provides as its output a temperaturedrop signal TD when the detected temperature is a predeterminedtemperature or below.

The time clocking circuit 2 provides as its outputs the hand movementsignal DS2 indicative of a drop in the voltage when it receives thevoltage drop signal BD from the voltage detection circuit 3, the handmovement signal DS3 indicative of a drop in the temperature when itreceives the temperature drop signal TD from the temperature detectioncircuit 4, and the hand movement signal DS1 in other normal states. FIG.3 illustrates waveforms of the hand movement signals DS1, DS2 and dS3 intheir respective states.

In FIG. 3, A represents a waveform of the hand movement signal DS1output at a cycle of one second in the normal state, B represents awaveform of the hand movement signal DS2 indicative of a drop in thebattery voltage, with 0.25 sec. interval two pulses being output at acycle of two seconds. C represents a waveform of the hand movementsignal DS3 indicative of the state of a drop in the temperature, with0.5 sec. Interval two pulses being output at a cycle of two seconds.

External input means 6 serves to output a reset signal RS, an alarm setsignal AS, a time correction signal TC, an alarm correction signal ACand a selection signal SE.

An alarm counter 5 resets its content in response to a receipt of thereset signal RS issued from the external input means 6 to synchronizethe time clocking circuit 2 with the alarm counter 5, and sets an alarmtime when it receives the alarm set signal AS with no reset signal RSreceived. The alarm counter 5 serves to output an alarm time set by theexternal input means 6. The alarm counter 5 further provides as itsoutput an alarm set signal AD each time the alarm time is set by thealarm set signal AS.

A coincidence circuit 7 provides as its output a coincidence signal TRwhen the alarm time AL from the alarm counter 5 is coincident with thetime data KL from the time clocking circuit 2. A warning circuit 8 isallowed to operate in response to a receipt of the coincidence signal TRfrom the coincidence circuit. The warning circuit 8 receives as itsinput the selection signal SE issued from the external input means 6 andselects for operation either the buzzer based warning or vibration basedwarning on the basis of the selection signal.

It is to be appreciated that in case the warning circuit 8 has receivedthe temperature drop signal TD from the temperature detection circuit 4,it is not allowed to operate in spite of the selection of the vibrationbased warning.

A first hand movement device 9 is a hand indicator mechanism forordinary hand indicator type electronic timepiece and accepts a handmovement signal DS1 every one second to move a second hand 20. A secondhand movement device 10 is a hand indicator mechanism for an alarm handand accepts the alarm set signal AD from the alarm counter 5 to move thehand.

During the time when the reset signal RS is being issued from theexternal input means 6, display times of the first hand movementmechanism 9 and the second hand movement mechanism 10 are corrected bythe time correction signal TC and the alarm correction signal AC issuedfrom the external input means 6.

Referring then to FIGS. 2(a) and 2(b), the first hand movement device 9consists of the second hand 20, a minute hand 21 and an hour hand 22, tothereby display a time. The second hand 20, minute hand 21 and hour hand22 are linked with one another by way of a gear train in such a mannerthat the minute and hour hands move in interlock with the second hand.The second hand movement device 10 consists of an alarm minute hand 23and an alarm hour hand 24, to thereby display an alarm set time. Thealarm minute hand 23 and the alarm hour hand 24 are linked with eachother by way of a gear train In such a manner that the alarm hour hand24 moves in interlock with the alarm minute hand 23.

FIG. 2(a) illustrates a reset state, that is, a state in which thesecond hand 20, minute hand 21 and hour hand 22 for the time display aresynchronized with the alarm minute hand 23 and alarm hour hand 24 forthe alarm time. The second hand 20, minute hand 21 and hour hand 22indicate a time 10:05'0", while the alarm minute hand 23 and alarm hourhand 24 indicate the same time 10:05. FIG. 2(b) illustrates a timedisplay in the normal state. The second hand 20, minute hand 21 and hourhand 22 indicate a time 10:05'25", while the alarm minute hand 23 andalarm hour hand 24 indicate an alarm set time 7:00.

Description will be made for the operation of the thus configuredelectronic timepiece in accordance with this embodiment.

The external means 6 is first operated to issue a reset signal RS. Thus,the timepiece results in its reset state. In this state, a timecorrection signal TC and an alarm correction signal AC are usedrespectively to set the first hand movement device 9 for the timedisplay and the second hand movement device 10 for the alarm timedisplay to the current time. A time 10:05 is then indicated both by thesecond hand 20, minute hand 21 and hour hand 22 constituting the firsthand movement device 9 and by the alarm minute hand 23 and alarm hourhand 24 constituting the second hand movement device 10, as shown inFIG. 2(a). The alarm counter 5 and the time clocking circuit 2 reset thecontent of the counter by use of a reset signal RS.

The external input means 6 are then operated to cancel the output of thereset signal RS. This allows the time clocking circuit 2 to start toissue a hand movement signal DS1 every one second as shown in FIG. 3A inresponse to an input of a hand movement reference signal KS. The firsthand movement device 9 accepts the hand movement signal DS1 to start thetime display. The time clocking circuit 2 further sends time data 3every one minute to the coincidence circuit 7. In such conditions,ordinary hand movements for the time display are carried out.

In case of setting the alarm time, the external input means 6 areoperated to provide an alarm set signal AS as its output to the alarmcounter 5. The alarm counter 5 sets an alarm time AL in conformity withthe alarm set signal AS. For instance, if the alarm counter 5 accepts a535 pulse alarm set signal AS, the content of the counter is set to 535,allowing the alarm time AL to be provided as 535 to the coincidencecircuit 7. The alarm counter 5 further provides 535 pieces of alarm setsignals AD as its output to the second hand movement device 10. As aresult, the second hand movement device 10 is allowed to indicate a timeof 535 minutes later, i.e., eight hours and 55 minutes later from 10:05of FIG. 2(a), that is, 7:00 shown in FIG. 2(b). The alarm time AL is setin minutes as described above.

Thus, when the count of the time data KL, the output of the timeclocking circuit 2 reaches 535 with the elapse of time, the coincidencecircuit 7 provides a coincidence signal TR as its output to the warningcircuit 8. After the receipt of the coincident signal TR, the waningcircuit 8 selects the warning method previously designated by theselection signal SE from the external input means 6, that is, either thebuzzer-based warning or the vibration based warning, to perform thewarning action.

The above operations are carried out in the ordinary state. Also, in theordinary state, the reference signal generation circuit 1 sends atemperature detection timing signal TS at predetermined intervals of,e.g., one hour to the temperature detection circuit 4, and sends avoltage detection timing signal VS every five minutes to the voltagedetection circuit 3. Upon the receipt of these signals, the temperaturedetection circuit 4 and the voltage detection circuit 3 perform theirrespective detecting actions and if the detected results are more thanthe predetermined detection values, both issue no signals.

In cases where the electronic timepiece is left alone at a lowtemperature, however, if it is judged that the detected temperature isthe predetermined temperature or below, then the temperature detectioncircuit 4 feeds a temperature drop signal TD to both the time clockingcircuit 2 and the warning circuit 8. The output of this temperature dropsignal TD continues until the detection result is updated by thesubsequent temperature detection timing signal TS. In response to areceipt of this temperature drop signal TD, the time clocking circuit 2issues a hand movement signal DS3 shown in FIG. 3C. This allows thesecond hand 20 to move twice at 0.5 sec. interval in two second cycle,resulting in a hand movement mode different from that in the ordinarystate.

The warning circuit 8 on the other hand prohibits the vibration basedwarning even though a coincidence signal TR has been received from thecoincidence circuit 7 for the duration when the temperature drop signalTD is being input.

If the voltage detection circuit 3 judges that the battery voltage is apredetermined voltage value or below, it supplies voltage drop signalsBD to both the time clocking circuit 2 and the warning circuit 8. Theoutput of this voltage drop signal BD continues until the detectionresult is updated by the subsequent voltage detection timing signal VS.In response to a receipt of this voltage drop signal BD, the timeclocking circuit 2 issues a hand movement signal DS2 shown in FIG. 3B.As a result of this, the second hand 20 is allowed to move twice at 0.25sec. interval in two second cycle, resulting in a hand movement modedifferent from that in the ordinary state and the temperature dropstate.

The warning circuit 8 on the other hand prohibits the vibration basedwarning and buzzer based warning even if the coincidence signal TR hasbeen received from the coincidence circuit 7 during the time when thevoltage drop signal BD is being input.

According to the electronic timepiece having the above configuration,any unnecessary waste of the battery is prevented and the user is warnedof the state of the battery and the temperature in the timepiece by wayof the manners of hand movements.

The present invention may be also useful in the following case. Forinstance, in case a plurality of persons wearing time pieces with buzzeralarm function have dived into the sea, even though one of theirtimepieces has issued an alarm, the wearers may not tell whose one hasissued the alarm. This is due to the fact that the sound transmissionspeed in the water is about four times faster than that in the air sothat there is little difference in times required for the sound to reachthe right and left ears of wearers. This makes it difficult to tell thetimepiece worn by which wearer has issued an alarm. That is, it is alsopossible to prohibit the vibration and/or buzzer based warning even inthe case of using under the environment extremely different from theordinary air pressure and to inform the user of the states by way of thehand movements.

INDUSTRIAL APPLICABILITY

The present invention is applicable to not only electronic wristwatchesbut also to various types of small-sized electronic equipment having anelectronic timepiece function with alarm.

What is claimed is:
 1. An electronic timepiece comprising:a referencesignal generating circuit for generating reference signals; a timeclocking circuit for counting the reference signals from said referencesignal generating circuit to provide time information as its output;warning means for warning a user of a specific time on a basis of timeinformation derived from said time clocking circuit; and timepiece statedetection means for detecting states of temperature and power sourcevoltage of said timepiece, said detection means stopping an operation ofthe warning means if one of a detection value of the temperature and adetection value of the power source voltage deviates from acorresponding predetermined value, said detection means allowing thetime clocking circuit to provide timing informations different from eachother when the detection means detects a temperature lower than thepredetermined value and when the detection means detects a voltage lowerthan the predetermined value, said timing informations being differentfrom a timing of the time information in a normal state.
 2. Theelectronic timepiece according to claim 1, wherein said timepiece statedetection means includes a plurality of detection circuits, one of whichis a timepiece temperature detection circuit for detecting thetemperature.
 3. The electronic timepiece according to claim 1, whereinsaid timepiece state detection means includes a plurality of detectioncircuits, one of which is a power source voltage detection circuit fordetecting the power source voltage.
 4. The electronic timepieceaccording to claim 1, wherein said warning means comprises buzzer basednoise warning means and vibration motor based silent warning means. 5.The electronic timepiece according to claim 4, wherein if thetemperature of said electronic timepiece detected by said detectionmeans is a predetermined temperature or below, on action of saidvibration motor based warning means is brought to a stop.
 6. Theelectronic timepiece according to claim 5, wherein if the power sourcevoltage of said electronic timepiece detected by said detection means isa predetermined voltage or below, the action of said buzzer based noisewarning means is brought to a stop.
 7. The electronic timepieceaccording to claim 2, wherein detection of the temperature of saidelectronic timepiece by said temperature detection circuit is carriedout at a certain cycle on a basis of the signals from said referencesignal generating circuit.
 8. The electronic timepiece according toclaim 3, wherein detection of the power source voltage at saidelectronic timepiece by said voltage detection circuit is carried out ata cycle different from a cycle of the temperature detection by saidtemperature detection circuit, on a basis of the signals from saidreference signal generating circuit.
 9. The electronic timepieceaccording to claim 1, wherein the timing of the time information in thenormal state indicates one second for every second, said timinginformations of the detection means being different in intervals forindicating time.